Mask

ABSTRACT

A mask configured to be attached to the face of a subject includes a wall section that defines an internal space and covers at least a portion of a nose and a mouth of the subject, an expired gas introduction section that is disposed in the internal space and introduce the subject&#39;s expired gas, and a communication section defining a communication channel through which the subject&#39;s expired gas introduced from the expired gas introduction section is introduced into an expired gas concentration detection sensor. The position of the expired gas introduction section in the internal space is variable.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Applications No.2013-212348 filed on Oct. 9, 2013, the contents of which areincorporated herein by reference.

BACKGROUND

The presently disclosed subject matter relates to a mask which isattached to the face of a subject so as to introduce the expired gas ofthe subject to an expired gas concentration detection sensor.

As an example of such a mask, Patent Document 1 discloses an oxygen maskwhich includes a wall section, an expired gas introduction section, anda communication section. The wall section defines an internal space ofthe mask so as to cover at least a portion of a nose and a mouth of thesubject. The expired gas introduction section is disposed in theinternal space so as to introduce the expired gas of the subject. Thecommunication section defines a communication channel which is supportedby the wall section and through which the expired gas of the subject isintroduced into an expired gas concentration detection sensor.

[Patent Document 1] JP-A-2011-115543

The shape of the faces to which such a mask is attached is different foreach subject. Particularly, the shape of a nose to which the expired gasintroduction section is in close proximity is different for eachsubject. Owing to this difference in facial shapes, the expired gas ofthe subject is often not surely introduced into the expired gasconcentration detection sensor.

Accordingly, the presently disclosed subject matter aims as providingthe technique to make sure the introduction of the expired gas of asubject to an expired gas concentration detection sensor regardless ofthe subjects' facial shapes.

SUMMARY

(1) According to an aspect of the presently disclosed subject matter, amask configured to be attached to the face of a subject includes a wallsection that defines an internal space and covers at least a portion ofa nose and a mouth of the subject, an expired gas introduction sectionthat is disposed in the internal space and introduce the subject'sexpired gas, and a communication section that defines a communicationchannel through which the subject's expired gas introduced from theexpired gas introduction section is introduced into an expired gasconcentration detection sensor. The position of the expired gasintroduction section in the internal space is variable.

According to this configuration, the expired gas introduction section ismovable to the position where the expired gas of the subject can besurely introduced. Thus, the expired gas can be surely introduced intothe expired gas concentration detection sensor regardless of subject'sfacial shapes.

(10) According to another aspect of the presently disclosed subjectmatter, a mask configured to be attached to the face of a subjectincludes a wall section that defines an internal space and covers atleast a portion of a nose and a mouth of the subject, an expired gasintroduction section that is disposed in the internal space andintroduces the subject's expired gas, and a communication section thatdefines a communication channel through which the subject's expired gasintroduced from the expired gas introduction section is introduced intoan expired gas concentration detection sensor. The expired gasintroduction section includes a partition part which defines a firstopening part opening against the subject's face when the subject wearsthe mask, and a second opening part opening upwards.

According to this configuration, the expired gas from the mouth can besurely introduced into the communication channel through the firstopening part, and the expired gas from the nose can be surely introducedinto the communication channel through the second opening part.Particularly, the second opening part opens upwards, so that the expiredgas from the nose can be surely introduced into the communicationchannel therethrough, regardless of the difference in the nasal shapesof subjects. Accordingly, the expired gas can be surely introduced intothe expired gas concentration detection sensor regardless of subject'sfacial shapes.

(2) The mask of the configuration (1) further includes a bridge partthat connects the wall section and the expired gas introduction section,and the bridge part is stretchable.

A portion of the face (particularly, the nose) may often contact theexpired gas introduction section depending upon the subjects' facialshapes. In this case, with the bridge part being extended, the expiredgas introduction section moves forward in the internal space of the wallsection, thereby possibly preventing the generation of an excessivecontact pressure against the subject's face. This avoids making thesubject uncomfortable, ensuring that the mask is readily maintained at aproper attachment position. Accordingly, the expired gas can be surelyintroduced into the expired gas concentration detection sensorregardless of subjects' facial shapes.

(3) In the mask of the configuration (2), the bridge part includes acorrugated part.

According to this configuration, it is possible to obtain a great degreeof extension while securing the strength to support the expired gasintroduction section. This more securely avoids making the subjectuncomfortable, and ensures that a proper disposition of the expired gasintroduction section is maintained. Accordingly, the expired gas can besurely introduced into the expired gas concentration detection sensorregardless of subjects' facial shapes.

(4) In the mask of any one of the configurations (1) to (3), thecommunication section and the expired gas introduction section arecoupled in such a manner as to be relatively movable with respect toeach other.

According to this configuration, the initial position of the expired gasintroduction section in the internal space can be changed depending uponthe facial shape of subject to which the mask is attached. For example,the expired gas can be introduced into the position at which the expiredgas introduction section cannot contact the subject's nose or into whichthe expired gas can be more surely introduced. Accordingly, the expiredgas can be surely introduced into the expired gas concentrationdetection sensor regardless of subjects' facial shapes.

(5) In the mask of any one of the configurations (1) to (4), the expiredgas introduction section is supported by the communication section, andthe mask further includes an adjusting mechanism that adjusts asupporting position at which the communication section is supported bythe wall section.

According to this configuration, the initial position of the expired gasintroduction section in the internal space can be changed depending uponthe facial shape of subject to which the mask is attached. For example,the expired gas can be introduced into the position at which the expiredgas introduction section cannot contact the subject's nose or into whichthe expired gas can be more surely introduced. Accordingly, the expiredgas can be surely introduced into the expired gas concentrationdetection sensor regardless of subjects' facial shapes.

(6) In the mask of the configuration (5), the adjusting mechanismincludes a mechanism that adjusts the supporting position by elasticdeformation of the wall section.

According to this configuration, there is no need to provide acomplicated structure for enabling the position of the communicationsection supported by the wall section to be able to be regulated.Accordingly, the expired gas can be surely introduced into the expiredgas concentration detection sensor regardless of the difference in thesubjects' facial shapes, without excessively increasing the cost.

(8) The mask of any one of the configurations (1) to (7) furtherincludes a sensor support that supports an expired gas concentrationdetection sensor which includes a light-emitting device and alight-receiving device so that light emitted from the light-emittingdevice passes across a light-passing portion of the communicationchannel. The sensor support has a vent hole by which the outside of thewall section communicate with the communication channel, and the venthole is formed on the sensor support so as not to overlap with thelight-passing portion of the communication channel in a passingdirection of the light-passing portion.

According to this configuration, it is possible to prevent theintroduction of external air with ventilation. This prevents the inverseaffection of the introduction of external air on the detection of theexpired gas concentration in the detection space. Further, it ispossible to discharge the expired gas quickly by means of a vent hole.Accordingly, along with the above-mentioned function of regulating theposition of the expired gas introduction section, there is provided afunction of precisely detecting the concentration of the subject'sexpired gas.

(9) The mask of the configuration (8) further includes an oxygen-supplysection that communicates with the internal space and holds one end ofan oxygen-supply tube, and a holding section that detachably holds asignal line connected to the expired gas concentration detection sensor.The oxygen-supply section and the holding section are arrangedsymmetrically with respect to the sensor support which is interposedbetween the oxygen-supply section and the holding section.

According to this configuration, the oxygen-supply tube and the signalline can be drawn symmetrically in the left and right sides of the mask,so it is possible to stabilize the posture of the mask with respect tothe subject's face. Accordingly, along with the above-mentioned functionof regulating the position of the expired gas introduction section,there is provided both the function of precisely detecting theconcentration of the subject's expired gas and the function of stablysupplying oxygen to the subject.

When combined with the configuration having the bridge part whichconnects the wall section and the inspired air introduction section, thebridge part scatters oxygen to be introduced into the internal space soas to homogenize the concentration of oxygen in the internal space.Further, oxygen to be injected in the internal space from theoxygen-supply section does not directly contact the subject's face,thereby preventing the skin from becoming dry.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front perspective view of a mask according to an embodimentof the presently disclosed subject matter.

FIG. 2 is a rear perspective view of the mask of FIG. 1.

FIGS. 3A and 3B are front perspective views of portions of the mask ofFIG. 1.

FIGS. 4A and 4B are rear perspective views of a portion of the mask ofFIG. 1.

FIGS. 5A and 5B are perspective views of a communication section and asensor to be provided in the mask.

FIG. 6 is a front view of the sensor being mounted on the mask of FIG.1.

DETAILED DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of the presently disclosed subject matter will nowbe described in detail with reference to the accompanying drawings. Theterms ‘right side’ and ‘left side’ used herein respectively denote theright direction and left direction seen from a subject who wears themask.

FIG. 1 is a perspective view showing an appearance of a mask 1 accordingto an embodiment of the presently disclosed subject matter when viewedobliquely from the right front side thereof. FIG. 2 is a perspectiveview showing an appearance of the mask 1 when viewed obliquely from theleft rear side thereof. The mask 1 to be attached to the subject's faceincludes a wall section 2, an expired gas introduction section 3, and acommunication section 4.

The wall section 2 is formed into a dome-shaped appearance which iscomposed of an elastic material. The wall section 2 has the size andshape which cover at least a portion of a nose and a mouth of thesubject. An edge part 2 a on the rear side of the wall section 2contacts the subject's face. The wall section 2 defines an internalspace 2 b therein. The wall section 2 has an opening 2 c on the frontside thereof. The opening 2 c allows the internal space 2 b and theoutside of the wall section to communicate with each other.

The expired gas introduction section 3 is disposed in the internal space2 b of the wall section 2. The expired gas introduction section 3 isprovided with a partition part 3 c which defines first and secondopening parts 3 a and 3 b. The first opening part 3 a opens towards theface of the subject who wears the mask 1. The second opening part 3 bopens upwards when the mask is attached to the face of the subject. Whenthe mask 1 is attached, a mouth and a nose of the subject arerespectively provided in close proximity to the first and second openingparts 3 a and 3 b.

The expired gas introduction section 3 defines an introduction space 3 dwhich communicates with the first and second opening parts 3 a and 3 b.The expired gas introduction section 3 introduces the expired gas fromthe mouth and nose of the subject into the introduction space 3 dthrough the first and second opening parts 3 a and 3 b. The expired gasintroduction section 3 is provided on the front side with a connectionpart 3 e which defines a communication channel communicating with theintroduction space 3 d.

The communication section 4 is supported by the wall section 2. The rearside of the communication section 4 is coupled with the connection part3 e of the expired gas introduction section 3. The communication section4 defines a communication channel therein. The communication channelcommunicates with the introduction space 3 d of the expired gasintroduction section 3 via the connection part 3 e. The communicationchannel introduces the expired gas from the expired gas introductionsection 3 into the expired gas concentration detection sensor.

In the mask 1 according to the present embodiment, the expired gasintroduction section 3 is disposed in the internal space 2 b of the wallsection 2 so as to be repositionable within the internal space 2 b.

According to this configuration, the expired gas introduction section 3is movable to a place to which the subject's expired gas is surelyintroduced. Accordingly, the expired gas can be surely introduced intothe expired gas concentration detection sensor regardless of subject'sfacial shapes.

The expired gas introduction section 3 has the first and second openingparts 3 a and 3 b divided by the partition part 3 c. The first openingpart 3 a opens towards the face of the subject who wears the mask 1. Thesecond opening part 3 b opens upwards when the mask is attached to theface of the subject. According to this configuration, the expired gasfrom the mouth and the nose can be surely introduced into theintroduction space 3 d through the first and second opening parts 3 aand 3 b, respectively. Particularly, since the second opening part 3 bopens upwards, the expired gas from the nose is surely introduced intothe introduction space 3 d regardless of the difference in subject'snasal shapes. Accordingly, the expired gas is surely introduced into theexpired gas concentration detection sensor regardless of subject'sfacial shapes.

A detailed configuration for variable displacement of the expired gasintroduction section 3 in the internal space 2 b of the wall section 2will now be described.

As shown in FIG. 2, the mask 1 includes a right bridge part 5 a and aleft bridge part 5 b. The right bridge part 5 a connects the right sideof the wall section 2 and the right side of the expired gas introductionsection 3. The left bridge part 5 b connects the left side of the wallsection 2 and the left side of the expired gas introduction section 3.The right and left bridge parts 5 a and 5 b are respectively stretchablein their longitudinal directions. Specifically, the right and leftbridge parts 5 a and 5 b is each provided with a corrugated part 5 a 1,5 b 1. The corrugated parts 5 a 1 and 5 b 1 respectively allow the rightand left bridge parts 5 a and 5 b to be flexibly extended in therespective longitudinal directions.

A right end of the right bridge part 5 a has an extension which furtherextends out of the right side of the wall section 2, and the extensionis provided with a through-hole 5 a 2. A left end of the left bridgepart 5 b has an extension which further extends out of the left side ofthe wall section 2, and the extension is provided with a through-hole 5b 2. The through-holes 5 a 2 and 5 b 2 are elements through whichstrings pass so that the strings are hung around subject's ears to holdthe mask 1 over the subject's face.

A portion of the face (particularly, the nose) may often contact theexpired gas introduction section 3 depending upon the subject's facialshapes. In this case, with the right and left bridge parts 5 a and 5 bbeing extended, the expired gas introduction section 3 moves forward inthe internal space 2 b of the wall section 2, thereby possiblypreventing the generation of an excessive contact pressure against thesubject's face. This avoids making the subject uncomfortable, ensuringthat the mask 1 is readily maintained at a proper attachment position.Accordingly, the expired gas is surely introduced into the expired gasconcentration detection sensor regardless of subject's facial shapes.

Particularly, the right and left bridge parts 5 a and 5 b arerespectively provided with corrugated parts 5 a 1 and 5 b 1, enablingthe right and left bridge parts 5 a and 5 b to be stretchable, so thatit is possible to obtain a great degree of extension while securing thestrength to support the expired gas introduction section 3. This moresecurely avoids making the subject uncomfortable, and ensures that aproper disposition of the expired gas introduction section 3 ismaintained. Accordingly, the expired gas can be surely introduced intothe expired gas concentration detection sensor regardless of subject'sfacial shapes.

As shown in FIG. 1, the wall section 2 has right and left support parts6 and 7 on the front side thereof. The communication section 4 isinterposed between the right and left support parts 6 and 7 and issupported by the wall section 2.

FIG. 3A is a perspective view showing an appearance of the mask 1 withthe communication section 4 and the right and left support parts 6 and 7removed. FIG. 3B is a perspective view showing an appearance of theright and left support parts 6 and 7.

A shown in FIG. 3A, an opening 2 c formed on the front side of the wallsection 2 has a right slit 2 c 1 extending in the right side and a leftslit 2 c 2 extending in the left side. A base end portion of the rightslit 2 c 1 is provided on upper and lower sides thereof with right hookprotrusions 2 d 1 (the lower side protrusion is only shown in FIG. 3A,and the upper side protrusion is shown in FIG. 2) which extendrearwards. A base end portion of the left slit 2 c 2 is provided onupper and lower sides thereof with left hook protrusions 2 d 2 (thelower side protrusion is only shown in FIG. 3A) which extend rearwards.

The expired gas introduction section 3 is provided on the front sidewith a connection part 3 e which extends forwards. A circumferentialwall constituting the connection part 3 e defines a communicationchannel which communicates with the introduction space 3 d. Theconnection part 3 e is provided on the front end surface with anengaging part 3 e 1 which protrudes inwards from the inner surface ofthe circumferential wall, narrowing the communication channel.

As shown in FIG. 3B, the right support part 6 includes a right base 6 a,a pair of right engaging pieces 6 b, and a right connector 6 c. Theright base 6 a extends rearwards in an arc form (see FIG. 1). The rightsupport part 6 is made of a harder material than the wall section 2, buta rear end portion of the right base 6 a has flexibility with which therear end portion coincides with the shape of the wall section to whichthe right support part is attached. The pair of right engaging pieces 6b extends upwards and downwards from the front end surface of the rightbase 6 a. The respective right engaging piece 6 b is provided with aright through-hole 6 b 1. The right connector 6 c is provided with apair of right plate portions 6 c 1 which extends leftwards from thefront end surface of the right base 6 a. The pair of right plateportions 6 c 1 is connected by a right rod portion 6 c 2 which extendsvertically. The respective right plate portion 6 c 1 is provided with aright through-hole 6 c 3.

The left support part 7 includes a left base 7 a, a pair of leftengaging pieces 7 b, and a left connector 7 c. The left base 7 a extendsrearwards in an arc form. The left support part 7 is made of a hardermaterial than the wall section 2, but a rear end portion of the leftbase 7 a has flexibility with which the rear end portion coincides withthe shape of the wall section to which the left support part isattached. The pair of left engaging pieces 7 b extends upwards anddownwards from the front end surface of the left base 7 a. Therespective left engaging piece 7 b is provided with a left through-hole7 b 1. The left connector 7 c is provided with a pair of left plateportions 7 c 1 which extends leftwards from the front end surface of theleft base 7 a. The pair of left plate portions 7 c 1 is connected by aleft rod portion 7 c 2 which extends vertically. The respective leftplate portion 7 c 1 is provided with a left through-hole 7 c 3.

The right support part 6 is mounted in such a manner that the pair ofright engaging pieces 6 b is disposed on the rear side of the right slit2 c 1 of the wall section 2. Here, the respective right engagingprotrusions 2 d 1 are inserted through the right correspondingthrough-holes 6 b 1 so as to hold the right support part 6 on the wallsection 2. The left support part 7 is mounted in such a manner that thepair of left engaging pieces 7 b is disposed on the rear side of theleft slit 2 c 2 of the wall section 2. Here, the respective leftengaging protrusions 2 d 2 are inserted through the left correspondingthrough-holes 7 b 1 so as to hold the left support part 7 on the wallsection 2.

FIG. 4A is a perspective view showing an appearance of the communicationsection 4 when obliquely viewed from the left rear side thereof. Thecommunication section 4 has a connection part 4 a which extends forwardsand rearwards from the mask 1. The connection part 4 a defines acommunication channel therein. The connection part 4 a is provided onthe outer surface thereof with a plurality of protrusions 4 a 1, whichare arranged in the front-to-rear direction of the mask 1.

A shown in FIGS. 1 and 2, the connection part 4 a of the communicationsection 4 and the connection part 3 e of the expired gas introductionsection 3 are coupled together, and the communication channel defined bythe connection part 4 a and the communication channel defined by theconnection part 3 e communicate with each other. Specifically, theconnection parts 4 a and 3 e are coupled such that the outer surface ofthe connection part 4 a faces against the inner surface of theconnection part 3 e. Here, the protrusion 4 a 1 formed on the outersurface of the connection part 4 a is engaged with the engaging part 3 e1 formed on the front end surface of the connection part 3 e, so thatthe connection part 3 e is positioned with respect to the connectionpart 4 a.

The connection part 3 e of the expired gas introduction part 3 iscomposed of a flexible material, and is coupled with the connection part4 a of the communication section 4 in such a manner that the connectionpart 3 e is slidable in the forward-rearward direction of the mask 1. Asdescribed above, since the connection part 4 a is provided on the outersurface thereof with the plurality of protrusions 4 a 1 in theforward-rearward direction of the mask 1, the position of the connectionpart 3 e with respect to the connection part 4 a is changeable byselecting the protrusion 4 a 1 to be engaged with the engaging part 3 e1 of the connection part 3 e. That is, the arrangement of the expiredgas introduction section 3 with respect to the communication section 4is changeable in the forward-rearward direction in the internal space 2b of the wall section 2.

According to this configuration, the initial position of the expired gasintroduction section in the internal space is changeable depending uponthe facial shape of subject to which the mask is attached. For example,the expired gas introduction section is movable into a position at whichthe expired gas introduction section does not contact with the subject'snose or into a position at which the expired gas is more surelyintroduced. Accordingly, the expired gas is surely introduced into theexpired gas concentration detection sensor regardless of subject'sfacial shapes.

As shown in FIG. 4A, the communication section 4 also has right and leftconnection parts 4 b and 4 c.

The right connection part 4 b is provided on the rear side thereof witha plurality of right grooves 4 b 1 which extends vertically. The rightgrooves 4 b 1 are arranged in the left-right direction of the mask 1.The right connection part 4 b is provided on upper and lower sidesthereof with right protrusions 4 b 2 in a pair (the upper-side rightprotrusion 4 b 2 is only shown).

The left connection part 4 c is provided on the rear side thereof with aplurality of left grooves 4 c 1 which extends vertically. The leftgrooves 4 c 1 are arranged in the left-right direction of the mask 1.The left connection part 4 c is provided on upper and lower sidesthereof with left protrusions 4 c 2 in a pair (the upper-side leftprotrusion 4 c 2 is only shown).

As shown in FIG. 4B, the right connection part 4 b is held between thepair of right plate portions 6 c 1 of the right connector 6 c by fittingthe pair of right protrusions 4 b 2 of the right connection part 4 b ofthe communication section 4 into the pair of right through-holes 6 c 3of the right connector 6 c of the right support part 6. Here, the rightrod 6 c 2 of the right connector 6 c is engaged with one of the rightgrooves 4 b 1.

Similarly, the left connection part 4 c is held between the pair of leftplate portions 7 c 1 of the left connector 7 c by fitting the pair ofleft protrusions 4 c 2 of the left connection part 4 c of thecommunication section 4 into the pair of left through-holes 7 c 3 of theleft connector 7 c of the left support part 7. Here, the left rod 7 c 2of the left connector 7 c is engaged with one of the left grooves 4 c 1.

Accordingly, the communication section 4 is interposed between the rightand left support parts 6 and 7 and is supported by the wall section 2.Here, the right connection part 4 b is able to rotate about the pair ofright protrusions 4 b 2. Similarly, the left connection part 4 c is ableto rotate about the pair of left protrusions 4 c 2.

When the right and left support parts 6 and 7 are pressed from the leftand right sides, the wall section 2 is deformed such that the width inthe left-right direction is narrowed due to the flexibility of the rightand left bases 6 a and 7 a. Thereby, the right and left connectors 6 cand 7 c is moved opposite in the left-right direction of the mask 1, sothat the engagement between the right rod 6 c 2 and the right groove 4 b1 of the right connector 4 b and the engagement between the left rod 7 c2 and the left groove 4 c 1 of the left connector 4 c are released. Theright rod 6 c 2 comes to be engageable with another right groove 4 b 1.The left rod 7 c 2 comes to be engageable with another left groove 4 c1.

With the right and left rods 6 c 2 and 7 c 2 respectively opposed toother right and left grooves 4 b 1 and 4 c 1, when the right and leftsupport parts 6 and 7 are press-released, the wall section 2 elasticallyreturns to its original shape and the right and left connectors 6 c and7 c are moved outwards in the left-eight direction of the mask 1, sothat the right and left rods 6 c 2 and 7 c 2 are engaged with theabove-mentioned right and left grooves 4 b 1 and 4 c 1. Thereby, theright and left connection parts 4 b and 4 c respectively rotate aboutthe right and left protrusions 4 b 2 and 4 c 2, so that the relativeposition between the communication section 4 and the wall section 2changes. Thus, the arrangement of the expired gas introduction section 4coupled with the communication section 4 with respect to the wallsection 2 is changed in the forward-rearward direction in the internalspace 2 b of the wall section 2.

As set forth from the foregoing, the right and left connectors 6 c and 7c of the right and left support parts 6 and 7, and the right and leftconnection parts 4 b and 4 c of the communication section 4 constitutean adjusting mechanism 8 which adjusts the position of the communicationsection 4 supported by the wall section 2.

According to this configuration, the initial position of the expired gasintroduction section 3 in the internal space 2 b is changeable dependingupon the facial shape of subject to which the mask 1 is attached. Forexample, the expired gas is introduced into the position at which theexpired gas introduction section 3 cannot contact the subject's nose orinto which the expired gas can be more surely introduced. Accordingly,the expired gas is surely introduced into the expired gas concentrationdetection sensor regardless of subject's facial shapes.

Particularly, since the position at which the communication section 4 issupported by the wall section 2 with the elastic deformation of the wallsection 2 is adjustable in the adjusting mechanism 8, a complicatedstructure is not required. Accordingly, the expired gas is surelyintroduced into the expired gas concentration sensor regardless of thedifference in the subject's facial shapes, without excessivelyincreasing the cost.

As shown in FIG. 4A, the communication section 4 is further providedwith a sensor support 4 d. The sensor support 4 d has a middle part 4 d1, a right part 4 d 2, and a left part 4 d 3. The middle part 4 d 1 isprovided in front of the connection part 4 a. The right part 4 d 2extends rightwards from the middle part 4 d 1. The left part 4 d 3extends leftwards from the front side of the connection part 4 a.

FIG. 5A is a perspective view showing an appearance of the lower portionof the communication section 4 when viewed from the right front sidethereof. The middle part 4 d 1 defines a detection space whichcommunicates with the communication channel defined by the connectionpart 4 a. Thus, the detection space forms a portion of the communicationchannel. The right side of the middle part 4 d 1 is provided with aright light-transparent window 4 d 4. The left side of the middle part 4d 2 is provided with a left light-transparent window 4 d 5. The rightpart 4 d 2 defines a right holding space 4 d 6 which opens downwards.The right window 4 d 4 is disposed in the right holding space 4 d 6. Theleft part 4 d 3 defines a left holding space 4 d 7 which opensdownwards. The left window 4 d 5 is disposed in the left holding space 4d 7. The middle part 4 d 1 is provided on the lower surface thereof witha pair of engaging pieces 4 d 8.

FIG. 5B is a perspective view showing an appearance of a sensor 9 whichis mounted to the sensor support 4 d. As an expired gas concentrationdetection sensor, the sensor 9 is provided with a housing 9 a. Thehousing 9 a has a first to third parts 9 a 1, 9 a 2, and 9 a 3. Thefirst and second parts 9 a 1 and 9 a 2 are connected by the third part 9a 3, thereby defining a recessed part 9 a 4.

The sensor 9 is provided with a light-emitting device 9 b and alight-receiving device 9 c. The light-emitting device 9 b isaccommodated in the first part 9 a 1 of the housing 9 a. Thelight-receiving device 9 c is accommodated in the second part 9 a 2 ofthe housing 9 a. The light-emitting device 9 b and the light-receivingdevice 9 c are opposed each other from the recessed part 9 a 4. A cord 9d is connected to the sensor 9. The cord 9 d includes a signal linewhich transmits a drive signal for a light-emitting device 9 b and alight-detection signal by the light-receiving device 9 c to a displaywhich is not shown.

A description will be made of the sensor 9 being mounted to thecommunication section 4, with reference to FIGS. 5 and 6. FIG. 6 is afront view showing an appearance of the mask 1 in which the sensor 9 ismounted to the sensor support 4 d. The sensor 9 is mounted such that themiddle part 4 d 1 of the sensor support 4 d is fitted into the recessedpart 9 a 4. An engaging protrusion 4 d 8 formed on the middle part 4 d 1is engaged with the third part 9 a 3 of the housing 9 a. Accordingly,the first part 9 a 1 of the housing 9 a is held in the right holdingspace 4 d 6 defined by the right part 4 d 2. The second part 9 a 2 ofthe housing 9 a is held in the left holding space 4 d 7 defined by theleft part 4 d 3. Here, the light-emitting device 9 b is opposed to theright window 4 d 4, and the light-receiving device 9 c is opposed to theleft window 4 d 5. That is, the sensor support 4 d supports the sensor 9such that light emitted from the light-emitting device 9 b passes acrossa portion of the communication channel.

Light emitted from the light-emitting device 9 b enters the detectionspace defined in the middle part 4 d 1 via the right window 4 d 4. Intothe detection space, the expired gas introduced from the expired gasintroduction section 3 is introduced via the communication channeldefined by the connection part 4 a of the communication section 4. Lightpassing through the detection space reaches the light-receiving device 9c via the left window 4 d 5. Light emitted from the light-emittingdevice 9 b has a wavelength capable of absorbing carbon dioxide as anexample of the expired gas. Since the intensity of light which reachesthe light-receiving device 9 c varies depending upon the concentrationof carbon dioxide contained in the subject's expired gas, theconcentration of carbon dioxide contained in the expired gas is detectedby monitoring the intensity of light.

As shown in FIG. 5A, the communication section 4 is further providedwith a vent part 4 e. The vent part 4 e is provided in front of themiddle part 4 d 1, and defines an internal space which communicates withthe detection space defined by the middle part 4 d 1. Accordingly, theinternal space forms a portion of the communication channel. A front endsurface of the vent part 4 e forms a closed wall 4 e 1. That is, thefront end of the communication channel, which extends in the directionperpendicular to the movement direction of light emitted from thelight-emitting device 9 b, is closed.

The vent part 4 e is provided with a vent hole 4 e 2 on the front rightside. As shown in FIG. 6, the vent part 4 e is also provided with thesame vent hole 4 e 2 on the front left side. The respective vent hole 4e 2 allows the outside of the wall section 2 and the communicationchannel to communicate with each other. The expired gas introduced intothe communication section 4 through the expired gas introduction section3 is discharged out through the respective vent holes 4 e 2. That is,the respective vent holes 4 e 2 allow the communication channel and theoutside of the wall section 2 to communicate with each other.

Since the vent hole 4 e 2 is arranged at a position that strays out ofthe detection space (a portion of the communication channel) acrosswhich light emitted from the light-emitting device 4 b passes, theintroduction of external air into the detection space which isaccompanied by the ventilation is prevented. This prevents an inverseaffection of the introduction of external air on the detection of theexpired gas concentration in the detection space. Further, the expiredgas is quickly discharged via the vent holes 4 e 2. Accordingly, alongwith the above-mentioned function of regulating the position of theexpired gas introduction section 3, there is provided a function ofprecisely detecting the concentration of the subject's expired gas.

As shown in FIG. 1, the mask 1 is further provided with an oxygen-supplysection 10 and a cord-holding section 11. The oxygen-supply section 10is disposed at a front side of the right support parts. The cord-holdingsection 11 is disposed at a frond side of the left support parts.

The oxygen-supply section 10 holds an end of an oxygen-supply tube 12.The oxygen-supply tube 12 may be integrally formed with theoxygen-supply section 12, or otherwise may be detachably attached to theoxygen-supply section 10. Although not shown in the drawings, the insideof the oxygen-supply section 10 communicates with the internal space 2 bof the wall section 2. Oxygen supplied from the outside through theoxygen-supply tube 12 is provided through the internal space 2 b inresponse to the subject's inspiration.

Here, the right and left bridge parts 5 a and 5 b scatter oxygen to beinjected into the internal space 2 b from the oxygen-supply section 10.Thereby, the concentration of oxygen in the internal space 2 b ishomogenized. Further, oxygen to be injected into the internal space 2 bfrom the oxygen-supply section 10 does not directly contact thesubject's face, thereby preventing the skin from becoming dry.

The cord-holding section 11 detachably holds a cord 9 d which isconnected to the sensor 9. FIG. 6 shows the cord 6 d being held by thecord-holding section 11. Further, the oxygen-supply section 10 and thecord-holding section 11 are arranged symmetrically in the left-rightdirection of the mask 1, with the sensor support 4 d of thecommunication section 4 interposed therebetween.

According to this configuration, the oxygen-supply tube 12 and the cord9 d is drawn symmetrically in the left-right direction of the mask 1, soit is possible to stabilize the posture of the mask 1 with respect tothe subject's face. Accordingly, along with the above-mentioned functionof regulating the position of the expired gas introduction section 3,there is provided both the function of precisely detecting theconcentration of the subject's expired gas and the function of stablysupplying oxygen to the subject.

The above-mentioned embodiments are merely provided for illustrativepurposes, but not limitative purposes. It is apparent that the presentlydisclosed subject matter may be changed/modified without departing fromthe spirit of the presently disclosed subject matter, and that theequivalents of the presently disclosed subject matter are included inthe scope of the presently disclosed subject matter.

When the mask 1 includes at least one of the flexibility of the rightand left bridge parts 5 a and 5 b, the slidability of the connectionpart 3 e of the expired gas introduction section 3 with respect to theconnection part 4 a of the communication section 4, and the adjustingmechanism 8, the position of the expired gas introduction section 3 inthe internal space 2 b of the wall section 2 is variable.

In the case where the adjusting mechanism 9 is omitted, thecommunication section 4 may not essentially be supported by the wallsection 2. For example, the communication section may be supported bythe expired gas introduction section 3, for example.

The configuration of the sensor support 4 d of the communication section4 may be properly changed depending upon the specification of the sensor9. For example, the sensor 9 in the former embodiment includes thehousing 9 a in which an accommodation part for the light-emitting device9 b and an accommodation part for the light-receiving device 9 c areintegrally formed. However, the accommodation part for thelight-emitting device 9 b and the accommodation part for thelight-receiving device 9 c may be separately formed.

What is claimed is:
 1. A mask configured to be attached to a face of asubject comprising: a wall section that defines an internal space and isadapted to cover at least a portion of a nose and a mouth of thesubject; an expired gas introduction section that is disposed in theinternal space and is adapted to introduce expired gas of the subject; acommunication section that defines a communication channel through whichthe expired gas introduced from the expired gas introduction section isintroduced into an expired gas concentration detection sensor; and abridge part that connects the wall section and the expired gasintroduction section, wherein the bridge part is stretchable, whereinthe bridge part includes a corrugated part, and wherein a position ofthe expired gas introduction section in the internal space is variable.2. The mask according to claim 1, wherein the communication section andthe expired gas introduction section are coupled so as to be relativelymovable with respect to each other.
 3. The mask according to claim 1,wherein the expired gas introduction section is supported by thecommunication section, wherein the mask further comprises an adjustingmechanism that adjusts a supporting position at which the communicationsection is supported by the wall section.
 4. The mask according to claim3, wherein the adjusting mechanism includes a mechanism that adjusts thesupporting position by elastic deformation of the wall section.
 5. Themask according to claim 1, wherein the expired gas introduction sectionincludes a partition part which defines a first opening part adapted toopen against the face of the subject when the subject wears the mask,and which defines a second opening part opening upwards.
 6. A maskconfigured to be attached to a face of a subject comprising: a wallsection that defines an internal space and is adapted to cover at leasta portion of a nose and a mouth of the subject; an expired gasintroduction section that is disposed in the internal space and isadapted to introduce expired gas of the subject; a communication sectionthat defines a communication channel through which the expired gasintroduced from the expired gas introduction section is introduced intoan expired gas concentration detection sensor; a sensor support thatsupports the expired gas concentration detection sensor, which includesa light-emitting device and a light-receiving device, so that lightemitted from the light-emitting device passes across a light-passingportion of the communication channel; an oxygen-supply section thatcommunicates with the internal space and holds one end of anoxygen-supply tube; and a holding section that detachably holds a signalline connected to the expired gas concentration detection sensor,wherein a position of the expired gas introduction section in theinternal space is variable, wherein the sensor support has a vent holethrough which an outside of the wall section and the communicationchannel communicate with each other, wherein the vent hole is formed onthe sensor support so as not to overlap with the light-passing portionof the communication channel in a passing direction of the light-passingportion, and wherein the oxygen-supply section and the holding sectionare arranged symmetrically with respect to the sensor support which isinterposed between the oxygen-supply section and the holding section.